CVE-2026-48804: python-socketio · Binary attachment accumulation can cause denial of service
Affects python-socketioSource GCVE Database
Not known to be exploited · CVSS 7.5 High : upgrade to 5.16.2 soon.
Data as of 29 Oct 2026, 19:04 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 41% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.16.2
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 11 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.
What to do
Upgrade python-socketio to 5.16.2.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| PyPIpython-socketio | Affected
| Fixed in
|
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Description
### Impact The python-socketio server stores binary `EVENT` and `ACK` messages in memory while it waits to receive their binary attachments. Once all the attachments are received, these messages are then processed. An attacker can submit a binary message and intentionally omit sending one or more of its attachments to cause the message along with the partial list of received attachments to stay in memory for a long time. ### Patches Version 5.16.2 takes the following measures to address this issue: - Binary packets are only accepted from authenticated clients. - When a client disconnects, the server checks if there is a partial binary message being held for the client and deletes it.